FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_once.c
1 /* $NetBSD: subr_once.c,v 1.3 2006/01/16 21:45:38 yamt Exp $ */
2
3 /*-
4 * Copyright (c)2005 YAMAMOTO Takashi,
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __KERNEL_RCSID(0, "$NetBSD: subr_once.c,v 1.3 2006/01/16 21:45:38 yamt Exp $");
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/proc.h>
35 #include <sys/once.h>
36
37 int
38 _run_once(once_t *o, int (*fn)(void))
39 {
40 int error = 0;
41
42 simple_lock(&o->o_lock);
43 while ((o->o_flags & ONCE_RUNNING) != 0) {
44 ltsleep(o, PUSER, "runonce", 0, &o->o_lock);
45 }
46 if (o->o_flags & ONCE_DONE) {
47 goto done;
48 }
49 o->o_flags |= ONCE_RUNNING;
50 simple_unlock(&o->o_lock);
51
52 error = (*fn)();
53
54 simple_lock(&o->o_lock);
55 if (error == 0) {
56 o->o_flags = ONCE_DONE;
57 }
58 wakeup(o);
59 done:
60 simple_unlock(&o->o_lock);
61
62 return error;
63 }
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